What Is the Diagnostic Accuracy of Flat-panel Cone-beam CT Arthrography for Diagnosis of Scapholunate Ligament Tears?

BACKGROUND: Cone beam CT (CBCT) is a widely available technique with possible indications in carpal ligament injuries. The accuracy of CBCT arthrography in diagnosing traumatic tears of the scapholunate ligament has not been reported. QUESTIONS/PURPOSES: (1) What is the diagnostic accuracy of CBCT and how does it relate to the accuracy of multislice CT arthrography and conventional arthrography in diagnosing scapholunate ligament tears? (2) What is the estimated magnitude of skin radiation doses of each method? METHODS: This secondary analysis of a previous prospective study included 71 men and women with suspected scapholunate ligament tears and indications for arthroscopy. Preoperative imaging was conventional arthrography and either MSCT arthrography for the first half of patients to be included (n = 36) or flat-panel CBCT arthrography for the remaining patients (n = 35). Index tests identified therapy-relevant SLL tears with dorsal or complete SLL ruptures, and these tears were compared with relevant SLL tears which were determined through arthroscopy as Geissler Stadium III and IV by probing the instable SL joint with a microhook or arthroscope. These injuries were treated by open ligament repair and Kirschner wire fixation. Accuracy values and 95% confidence intervals were calculated. Additional estimates of the radiation skin doses of each CBCT exam and two MSCT protocols were subsequently calculated using dose area products, dose length products, and CT dose indices. RESULTS: The diagnostic accuracy was high for all imaging methods. 95% CIs were broadly overlapping and therefore did not indicate differences between the diagnostic groups: Sensitivity of CBCT arthrography was 100% (95% CI 77 to 100), specificity was 95% (95% CI 76 to 99.9), positive predictive value was 93% (95% CI 68 to 99.8), and negative predictive value was 100% (95% CI 83 to 100). For MSCT arthrography, the sensitivity was 92% (95% CI 64 to 99.8), specificity was 96% (95% CI 78 to 99.9), positive predictive value was 92% (95% CI 64 to 99.8), and negative predictive value was 96% (95% CI 78 to 99.9). For conventional arthrography, the sensitivity was comparably high: 96% (95% CI 81 to 99.9). Specificity was (81% [95% CI 67 to 92]); the positive predictive value was 77% (95% CI 59 to 89) and negative predictive value was 97% (95% CI 86 to 99.9). Estimated mean (range) radiation skin doses were reported in a descriptive fashion and were 12.9 mSv (4.5 to 24.9) for conventional arthrography, and 3.2 mSv (2.0 to 4.8) for CBCT arthrography. Estimated radiation skin doses were 0.2 mSv and 12 mSv for MSCT arthrography, depending on the protocol. CONCLUSION: Flat-panel CBCT arthrography can be recommended as an accurate technique to diagnose scapholunate ligament injuries after wrist trauma. Estimated skin doses are low for CBCT arthrography and adapted MSCT arthrography protocols. LEVEL OF EVIDENCE: Level III, diagnostic study.

Stapes piston insertion depth and clinical correlations.

Background: The insertion of the stapes piston within the vestibule provides the physical basis for a successful stapedotomy. An insertion depth of 0.5 mm is recommended to avoid the dislocation of the stapes prosthesis (e.g. sneezing). Aims: The objective of this study is to analyze the depth of stapes prosthesis insertion and its correlation with clinical outcome. Material and methods: We observed in a retrospective case series 39 otosclerosis patients after a stapedotomy and a postoperative performed flat panel tomography/cone beam CT. The evaluation included the radiologically found depth of prosthesis insertion within the vestibule, the vestibule depth, and the correlation with the bone conduction (BC) threshold, vertigo, and tinnitus. Results: Insertion depth varied between 0.2 and 1.6 mm (mean 0.74 mm). The ratio of insertion depth versus the vestibule depth was between 8% and 59% (mean 26.6%). We observed no correlation between the insertion depth, the length of the prosthesis, the ratio of insertion depth/vestibule depth, postoperative BC, appearance of vertigo, or tinnitus. Conclusions and significance: In our group, we observed no significant relation between insertion depth of the stapes piston, postoperative vertigo, tinnitus, or decrease of the BC.

Cochlear implants and 1.5 T MRI scans: the effect of diametrically bipolar magnets and screw fixation on pain.

BACKGROUND: The probability that a patient will need an MRI scan at least once in a lifetime is high. However, MRI scanning in cochlear implantees is associated with side effects. Moreover, MRI scan-related artifacts, dislodging magnets, and pain are often the most frequent complications. The aim of this study was to evaluate the occurrence of pain in patients with cochlear implant systems using 1.5T MRI scans. METHODS: In a prospective case study of 10 implantees, an MRI scan was performed and the degree of pain was evaluated by a visual analog scale. Scans were performed firstly with and depending on the degree of discomfort/pain, without a headband. Four of the cochlear implants contained a screw fixation. Six cochlear implants contained an internal diametrically bipolar magnet. MRI observations were performed with a 1.5 T scanner. RESULTS: MRI scans were performed on all patients without causing any degree of pain, even without the use of a headband. CONCLUSION: Patients undergoing 1.5 T MRIs with devices including a diametrically bipolar magnet or a rigid implant screw fixation, experienced no pain, even without headbands.

MRI Artifacts and Cochlear Implant Positioning at 3 T In Vivo.

HYPOTHESIS: To evaluate the assessment of the internal auditory canal and the labyrinth in relation to different CI magnet positions and MRI sequences at 3 T. BACKGROUND: The indication criteria for cochlear implantation have been changed over the years and the growing number of implantations in patients after acoustic neuroma resections underline the importance of a postoperative MR imaging to assess the internal auditory canal (IAC) and the labyrinth. The MRI artifact induced by the cochlear implant magnet is a known problem that should be further observed by this investigation. METHODS: We compared the artifacts of Cochlear 512 magnets at different head positions in vivo at 3 T. The observed positions varied with a nasion-external ear canal angle of 90, 120, and 160 degrees and a variable distance of 5, 7, and 9 cm in relation to the external ear canal and different MRI sequences. RESULTS: The complete assessment of the internal auditory canal and labyrinth was possible with a magnet positioned at 90 degrees and 9 cm and 160 degrees and 9 cm. Evaluation of the IAC alone was possible with magnet positions at 90 degrees and 7 cm and 9 cm, 120 degrees and 9 cm, and 160 degrees and 7 cm and 9 cm. A high-resolution 3D T2w Drive sequence decreased the visibility of the structures significantly. A high-resolution TSE 2D T2w sequence together with one of the above-described positions allowed sufficient visualization of the structures. CONCLUSION: The position of the implant and the MRI sequence used determine the assessment of the IAC and the labyrinth at 3 T MRI. A position of the implant magnet at a nasion-external auditory canal angle which is more horizontal and posterior than so far commonly used allows a better visualization of the IAC and the labyrinth at 3 T.

Identification and revision of a displaced cochlear implant electrode in the internal auditory canal.

OBJECTIVE: The aim of the report is to underline the importance of a radiological technique which allows three-dimensional (3D) imaging of the cochlear implant electrode position postoperatively in cases of cochlear malformation, and to show a technique to prevent a repeat of cochlear implant electrode insertion in the internal auditory canal (IAC). CLINICAL PRESENTATION: This report describes the management of a case of insertion of a cochlear implant electrode into the IAC in a 1.5-year-old patient with an incomplete partition (IP) III cochlear malformation. INTERVENTION AND TECHNIQUE: The commonly used single plain postoperative X-ray is not sufficient to be certain of detecting the incorrect insertion of a cochlear implant electrode in the case of a malformed cochlea. In this case, 3D radiology allowed the incorrect insertion to be detected. The original cochlear implant electrode was temporarily left in place under the assumption that it would block the entrance to the IAC and prevent IAC insertion of the replacement electrode. CONCLUSION: Postoperative 3D radiological observation after cochlear implant surgery should be done in cases of malformation. Leaving the original electrode in place can help to prevent a repeat electrode malinsertion.

Accuracy of single-pass whole-body computed tomography for detection of injuries in patients with major blunt trauma.

BACKGROUND: Contrast-enhanced whole-body computed tomography (also called "pan-scanning") is considered to be a conclusive diagnostic tool for major trauma. We sought to determine the accuracy of this method, focusing on the reliability of negative results. METHODS: Between July 2006 and December 2008, a total of 982 patients with suspected severe injuries underwent single-pass pan-scanning at a metropolitan trauma centre. The findings of the scan were independently evaluated by two reviewers who analyzed the injuries to five body regions and compared the results to a synopsis of hospital charts, subsequent imaging and interventional procedures. We calculated the sensitivity and specificity of the pan-scan for each body region, and we assessed the residual risk of missed injuries that required surgery or critical care. RESULTS: A total of 1756 injuries were detected in the 982 patients scanned. Of these, 360 patients had an Injury Severity Score greater than 15. The median length of follow-up was 39 (interquartile range 7-490) days, and 474 patients underwent a definitive reference test. The sensitivity of the initial pan-scan was 84.6% for head and neck injuries, 79.6% for facial injuries, 86.7% for thoracic injuries, 85.7% for abdominal injuries and 86.2% for pelvic injuries. Specificity was 98.9% for head and neck injuries, 99.1% for facial injuries, 98.9% for thoracic injuries, 97.5% for abdominal injuries and 99.8% for pelvic injuries. In total, 62 patients had 70 missed injuries, indicating a residual risk of 6.3% (95% confidence interval 4.9%-8.0%). INTERPRETATION: We found that the positive results of trauma pan-scans are conclusive but negative results require subsequent confirmation. The pan-scan algorithms reduce, but do not eliminate, the risk of missed injuries, and they should not replace close monitoring and clinical follow-up of patients with major trauma.

Selection and placement of oral ventilation tubes based on tracheal morphometry.

OBJECTIVE/HYPOTHESIS: Evidence-based guidelines for the selection of appropriately sized ventilation tubes as well as their placement do not exist, although iatrogenic injuries to the trachea and larynx following endotracheal intubation are not infrequent. Our objective was to provide selection recommendations for ventilation tubes based on anatomic criteria. STUDY DESIGN: Prospective cross-sectional study at a tertiary care hospital. METHODS: From January 2010 to June 2010 all patients more than 16 years who underwent computer tomography of the neck were included. Contraindications were intubation, tracheotomy, fractures of the lower jaw, tumors, and head or neck deformities. Radiologic data was used to determine the distance between the lower incisors and cricoid cartilage and the smallest laryngotracheal diameter. The results were correlated with patient characteristics and compared with properties of ventilation tubes. RESULTS: One hundred fifty-nine patients were included in the study. The laryngotracheal constriction was subcricoidal with a mean diameter of 15.5 ± 3.2 mm coronal and 17.1 ± 2.6 mm sagittal. The mean distance between lower incisors and cricoid cartilage was 176.5 ± 14.8 mm. Patient height correlated significantly with the coronal subcricoid tracheal diameter (r = .51; P < .001) as well as with the distance between lower incisors and cricoid cartilage (r = .64; P < .001). No statistically significant gender or age-related correlations were found. Despite having the same specifications, tubes from different manufacturers differed considerably in their dimensions. CONCLUSIONS: Selection of size and placement of ventilation tubes can be based on patient height. Considerable differences in the dimensions of ventilation tubes necessitate a height-based nomogram for evidence-based tube selection and placement. A uniform system of tube labeling based on biometric data is required.

Postoperative monitoring of free vascularized bone grafts in reconstruction of bone defects.

Vascularized bone transfer is increasingly recognized as a very useful and versatile technique for reconstructing large bone defects. It is especially indicated in patients with challenging conditions, such as nonunions, postoncologic resections, severe trauma, and congenital defects. With increasing experience of reconstructive surgeons, improved microsurgical techniques, and more enhanced flaps, the failure rate of free flaps has been reduced in the last decades. Especially, the early-postoperative period is decisive in the outcome of surgery. Several techniques have been described for monitoring the postoperative viability of microsurgical free vascularized graft, and their sensitivity and reliability continues to be the object of animal experiments and clinical trials. The qualities of an optimal monitoring device should be objective, continuous, noninvasive, safe, reproducible, easily managed, and interpretable for the nursing staff, inexpensive, and a clear indicator of changes in arterial and venous circulation. Presently, no one neither fulfills all of the criteria completely nor is uniformly accepted. In this article, relative advantages and disadvantages of these various postoperative monitoring techniques are discussed.

In the line of fire--21st-century approach to an ancient war injury.

Authentic black-powder muzzle-loader weapons or replicas are used today primarily for re-enactments of historic battles. A lay actor playing the role of a Prussian infantryman sustained life-threatening gunshot injuries during a recent re-enactment of a historic battle of the Sixth Coalition. As only blank historic muzzle-loading weaponry was used, the origin of the missile causing the wounding was initially unclear. Further investigation revealed a ramrod that had been propelled out of the barrel of another gunner's smooth-bore gun as cause of injury. The ramrod was hurled on a trajectory of more than 20 m, breaking the victim's shouldered barrel and hitting the victim resulting in severe abdominal, thoracic, and upper limb injuries. The critical incidents while handling muzzle-loading weaponry leading to premature discharge are elucidated. Furthermore, this report demonstrates how actual diagnostics and subsequent surgical treatment enabled this infantryman to survive an injury to which his comrades-in-arms would have succumbed 200 years ago.

Functional outcomes and health-related quality of life after robot-assisted anterior cruciate ligament reconstruction with patellar tendon grafts.

During a short period of time, surgical robots had been propagated for automated tunnel placement in anterior cruciate ligament (ACL) reconstruction. Clinical outcome data are currently unavailable. Between 2000 and 2003, 152 patients underwent ACL replacement with the assistance of the Computer Assisted Surgical Planning and Robotics system (CASPAR, OrtoMaquet, Germany) at our hospital. After minimal invasive pin placement in both the tibia and femur, computed tomography was used to register anatomical landmarks and to plan graft tunnel alignment. The robot was used to drill tibial and femoral tunnels in an outside-in fashion according to pre-operative planning. There was one procedure-specific Serious Adverse Event (i.e., an intraoperative transection of the posterior cruciate ligament). After IRB approval, all patients were invited for a follow-up examination. Data from 100 patients (35 women, 65 men, mean age 35 [SD 11] years, median follow-up 61 [range 42-77] months) form the basis of this report. Side-to-side differences in anterior laxity were measured with the KT-1000 arthrometer. Patient-centered outcomes included the Lysholm-Score, the lower extremity functional scale (LEFS), and the Short Form 36 (SF36). The mean KT-1000 side-to-side difference was 0.89 [95% confidence interval (CI) 0.52-1.26] mm. Eight and five patients had a positive Lachman and pivot shift test, respectively. The Lysholm-Score averaged 86 (95% CI 83-89) points. Excellent, good, fair, and poor outcomes were reported by 38, 32, 20, and 10 patients. The LEFS averaged 85 (95% CI 82-88) points. The mean SF36 Physical Component Score was 48.4 (95% CI 46.5-50.3), indicating residual deficits compared to the population norm. All tibial graft tunnels did not cross the Blumensaat line, but were placed slightly anterior to the optimal center of 42% reported in previous studies. Compared to literature data, robot-assisted ACL reconstruction with BTB grafts may lead to higher knee stability, but poorer functional outcomes. The immense additional efforts with the procedure did not pay off in a benefit to patients.

Evaluation of cochlear implant electrode position after a modified round window insertion by means of a 64-multislice CT.

CONCLUSION: The modified round window insertion enables reproducible insertion into the scala tympani as demonstrated by comparing the 64-CT scanning data and the surgeon's reports. OBJECTIVE: To estimate the postoperative cochlear implant electrode position using a modified round window approach. PATIENTS AND METHODS: In a prospective study, 82 patients were operated via a modified round window approach to insert primarily into the scala tympani. Surgery had been performed from 2005 to 2008, implanting a Nucleus Freedom RECA device (Cochlear Corp.) (n = 43) or 90 k Helix device (Advanced Bionics Corp.) (n = 39). The array localization within the cochlea was determined by axial scanning overview, digital reconstruction of a 64-slice CT and by evaluation of the surgeon's report. RESULTS: In 78 (95.1%) patients, the array could be located in the scala tympani. In four cases, the position of the electrode was changed intracochlearly from the scala tympani to the scala vestibuli. In three additional cases, the scala vestibuli was inserted intentionally because the tympanic scale was found to be obstructed intraoperatively due to ossification. There were no significant differences between the intraoperative positioning and postoperative localization of the electrode arrays of the two manufacturers.

Diagnostic accuracy of plain radiographs and cineradiography in diagnosing traumatic scapholunate dissociation.

OBJECTIVE: Missed tears of the scapholunate ligament (SLL) and scapholunate dissociation (SLD) after wrist injuries pose a high risk of post-traumatic osteoarthritis of the carpus. Plain X-rays and dynamic radiographic studies are frequently used for initial diagnostic work-up. Given the limited evidence of their accuracy, we retrospectively compared the radiographic findings of patients with suspected traumatic SLD with wrist arthroscopy as the accepted reference standard. DESIGN AND METHODS: During a 6-year period, plain radiographs and DSA cineradiography scans were obtained from 198 patients who had sustained a hyperextension injury to their hand. Of those, 102 (72 men, 30 women, mean age of 42+/-12 years) subsequently underwent diagnostic arthroscopy. Digital images were reevaluated by experienced radiologists unaware of the arthroscopic findings for the presence or absence of SLD. We calculated the sensitivity (SN) and specificity (SP) with 95% confidence intervals (CI), and computed areas under the receiver operating characteristic curves (AUC/ROC). RESULTS: Arthroscopy revealed 42 SLL ruptures, 13, 10, and 19 of which were classified as grade I (partial), II (complete with dynamic instability), or III (complete with static instability) respectively. Plain radiographs correctly identified 24 injuries (SN 57.1%, 95% CI 41.0-72.3%), and produced 1 false-positive result (SP 98.3%, 95% CI 91.1-100.0%). The scapholunate distance and the SL angle contributed independently to the diagnostic variance, with an AUC/ROC of 85.7% (95% CI 76.8-92.2%). Cineradiography had a sensitivity of 36 out of 42 (85.7%, 95% CI 71.5-94.6%), and a specificity of 57 out of 60 (95.0%, 95% CI 86.1-99.0%). CONCLUSION: Pathological results on plain radiographs and cineradiography reliably indicate the presence of SLD after wrist trauma. Although non-conclusive, a negative dynamic study markedly reduces the pre-test probability of disease. Both methods remain key elements of primary diagnostic strategies for suspected traumatic SLD, and may facilitate the selection of additional tests.

Screening for blunt cerebrovascular injuries: the essential role of computed tomography angiography.

The implementation of aggressive diagnostics refuted the thesis that blunt cerebrovascular injuries (BCVI) are rare events. Given the estimates from recent studies, the prevalence may be as high as 1 per 100 among blunt multiple trauma patients. The morbidity and mortality of unrecognized and untreated BCVI is exceptionally high and warrants distinct efforts to detect these injuries during the primary trauma survey. The primary goal is to detect BCVI before neurological symptoms occur, and to introduce anticoagulation or antiplatelet therapy as appropriate. Index injuries such as cervical spine fractures increase the prior probability of disease, but are not helpful in ruling BCVI out. Computed tomography angiography (CTA) may represent the screening tool of choice, although there is still limited evidence about its accuracy. Pooled data from six studies (1368 patients) published between 2002 and 2006 suggest a sensitivity of 79% and a specificity of 97% in the trauma setting. In the two largest investigations, no false negative results were observed. Further research is needed to determine the efficacy of CTA for disclosing BCVI, and to evaluate the potential benefits to patients.

Predictive factors of liver injury in blunt multiple trauma.

INTRODUCTION: This study was conducted to clarify whether injuries that are likely to be revealed by initial clinical and conventional radiological examination at the trauma bay (e.g., right-side rib fractures) meaningfully contribute to the prior probability of accompanying hepatic lesions in multiple injured patients. MATERIAL AND METHODS: Fifty-five subjects (sampled from a cohort of 218 patients) with liver injury fulfilling the definition of polytrauma were compared with 55 polytrauma patients without liver injury. Controls were individually matched for age, gender, and Injury Severity Scores. Whole-body, helical, contrast-enhanced computed tomography was applied to all participants. We modeled independent predictors of liver involvement by conditional logistic and random-effects regression analysis. RESULTS: In the present sample, the prevalence of hepatic injury was 25.2%. Neither the injury mechanism (car crash, pedestrian accident, fall from height) nor certain accompanying injuries (right-side serial rib fractures, lumbar spine fractures) predicted the presence of hepatic injury. Liver injury was particularly unlikely in bikers [odds ratio (OR) 0.78, 95% confidence interval (CI) 0.59-1.03] and patients with left-side rib fractures (OR 0.80, 95% CI 0.66-0.98). DISCUSSION: There are no index injuries that will reliably indicate the presence of liver involvement in multiple trauma cases. Also, the absence of these injuries cannot rule out liver damage.

Resorbable screws versus pins for optimal transplant fixation (SPOT) in anterior cruciate ligament replacement with autologous hamstring grafts: rationale and design of a randomized, controlled, patient and investigator blinded trial [ISRCTN17384369].

BACKGROUND: Ruptures of the anterior cruciate ligament (ACL) are common injuries to the knee joint. Arthroscopic ACL replacement by autologous tendon grafts has established itself as a standard of care. Data from both experimental and observational studies suggest that surgical reconstruction does not fully restore knee stability. Persisting anterior laxity may lead to recurrent episodes of giving-way and cartilage damage. This might at least in part depend on the method of graft fixation in the bony tunnels. Whereas resorbable screws are easy to handle, pins may better preserve graft tension. The objective of this study is to determine whether pinning of ACL grafts reduces residual anterior laxity six months after surgery as compared to screw fixation. DESIGN/METHODS: SPOT is a randomised, controlled, patient and investigator blinded trial conducted at a single academic institution. Eligible patients are scheduled to arthroscopic ACL repair with triple-stranded hamstring grafts, conducted by a single, experienced surgeon. Intraoperatively, subjects willing to engage in this study will be randomised to transplant tethering with either resorbable screws or resorbable pins. No other changes apply to locally established treatment protocols. Patients and clinical investigators will remain blinded to the assigned fixation method until the six-month follow-up examination. The primary outcome is the side-to-side (repaired to healthy knee) difference in anterior translation as measured by the KT-1000 arthrometer at a defined load (89 N) six months after surgery. A sample size of 54 patients will yield a power of 80% to detect a difference of 1.0 mm +/- standard deviation 1.2 mm at a two-sided alpha of 5% with a t-test for independent samples. Secondary outcomes (generic and disease-specific measures of quality of life, magnetic resonance imaging morphology of transplants and devices) will be handled in an exploratory fashion. CONCLUSION: SPOT aims at showing a reduction in anterior knee laxity after fixing ACL grafts by pins compared to screws.

Blunt liver injuries in polytrauma: results from a cohort study with the regular use of whole-body helical computed tomography.

The estimated prevalence of liver injury in patients with blunt multiple trauma ranges from 1% to 8%. The objective of this study was to investigate the profile of accompanying liver injury in a cohort of polytraumatized patients who had regularly undergone contrast-enhanced, whole-body helical computed tomography (CT). We enrolled consecutive patients admitted between September 1997 and January 2001 to a level I trauma center. Clinical baseline data were compiled as part of a nationwide trauma registry. Morphologic features were evaluated descriptively, whereas prognostic variables were assessed by logistic regression analysis. We identified 218 patients [149 men, mean age 35 +/- 18 years, mean injury severity score (ISS) 35 +/- 10], 55 of whom had sustained blunt liver trauma [25.2%, 95% confidence interval (CI) 19.6-31.5%]. The prevalence of Moore III to V lesions was 10.1%. There were 99 parenchymal contusions, 15 capsular tears, and 2 liver fractures. Surgery was required in 15 patients and was best predicted by the classification of the American Association for the Surgery of Trauma [odds ratio (OR) 3.91, 95% CI 1.59-9.61]. The mortality rate was 0.0035/person/day. Patients requiring surgical repair had fourfold increased relative odds of case fatality (OR 4.50, 95% CI 1.01-19.96). Sevenfold increased relative odds were observed if liver laceration was considered the leading injury (OR 7.17, 95% CI 1.17-43.97). The prevalence of liver lacerations among multiple-trauma patients is likely to be underestimated and must be determined by the independent application of reference standards, such as helical CT. High-grade hepatic injuries and the need for surgical repair are associated with poorer survival prognosis.